psychologywikiaorg-20200213-history
Affective neuroscience
Affective neuroscience is the study of the neural mechanisms of emotion. This interdisciplinary field combines neuroscience with the psychological study of personality, emotion, and mood. Based on discoveries made through neural mapping of the limbic system, the neurobiological explanation of human emotion is that emotion is a pleasant or unpleasant mental state organized in the limbic system of the mammalian brain. If distinguished from reactive responses of reptiles, emotions would then be mammalian elaborations of general vertebrate arousal patterns, in which neurochemicals (e.g., dopamine, noradrenaline, and serotonin) step-up or step-down the brain's activity level, as visible in body movements, gestures, and postures. In mammals, primates, and human beings, feelings are displayed as emotion cues. For example, the human emotion of love is proposed to have evolved from paleocircuits of the mammalian brain (specifically, modules of the cingulated gyrus) designed for the care, feeding, and grooming of offspring. Paleocircuits are neural platforms for bodily expression configured millions of years before the advent of cortical circuits for speech. They consist of pre-configured pathways or networks of nerve cells in the forebrain, brain stem and spinal cord. They evolved prior to the earliest mammalian ancestors, as far back as the jawless fishes, to control motor function. Presumably, before the mammalian brain, life in the non-verbal world was automatic, preconscious, and predictable. The motor centers of reptiles react to sensory cues of vision, sound, touch, chemical, gravity, and motion with pre-set body movements and programmed postures. With the arrival of night-active mammals, circa 180 million years ago, smell replaced vision as the dominant sense, and a different way of responding arose from the olfactory sense, which is proposed to have developed into mammalian emotion and emotional memory. In the Jurassic Period, the mammalian brain invested heavily in olfaction to succeed at night as reptiles slept — one explanation for why olfactory lobes in mammalian brains are proportionally larger than in the reptiles. These odor pathways gradually formed the neural blueprint for what was later to become our limbic brain. Emotions are thought to be related to activity in brain areas that direct our attention, motivate our behavior, and determine the significance of what is going on around us. Pioneering work by Broca (1878), Papez (1937), and MacLean (1952) suggested that emotion is related to a group of structures in the center of the brain called the limbic system, which includes the hypothalamus, cingulate cortex, hippocampi, and other structures. More recent research has shown that some of these limbic structures are not as directly related to emotion as others are, while some non-limbic structures have been found to be of greater emotional relevance. Brain areas related to emotion Emotions are thought to be related to activity in brain areas that direct our attention, motivate our behavior, and determine the significance of what is going on around us. Pioneering work by Broca (1878), Papez (1937), and MacLean (1952) suggested that emotion is related to a group of structures in the center of the brain called the limbic system, which includes the hypothalamus, cingulate cortex, hippocampi, and other structures. More recent research has shown that some of these limbic structures are not as directly related to emotion as others, while some non-limbic structures have been found to be of greater emotional relevance. The following brain structures are currently thought to be most involved in emotion: * Amygdala — The amygdalae are two small, round structures located anterior to the hippocampi near the temporal poles. The amygdalae are involved in detecting and learning what parts of our surroundings are important and have emotional significance. They are critical for the production of emotion, and may be particularly so for negative emotions, especially fear. * Prefrontal cortex — The term prefrontal cortex refers to the very front of the brain, behind the forehead and above the eyes. It appears to play a critical role in the regulation of emotion and behavior by anticipating the consequences of our actions. The prefrontal cortex may play an important role in delayed gratification by maintaining emotions over time and organizing behavior toward specific goals. * Anterior cingulate — The anterior cingulate cortex (ACC) is located in the middle of the brain, just behind the prefrontal cortex. The ACC is thought to play a central role in attention, and may be particularly important with regard to conscious, subjective emotional awareness. This region of the brain may also play an important role in the initiation of motivated behavior. * Ventral striatum — The ventral striatum is a group of subcortical structures thought to play an important role in emotion and behavior. One part of the ventral striatum called the nucleus accumbens is thought to be involved in the experience of goal-directed positive emotion. Individuals with addictions experience increased activity in this area when they encounter the object of their addiction. * Insula — The insular cortex is thought to play a critical role in the bodily experience of emotion, as it is connected to other brain structures that regulate the body’s autonomic functions (heart rate, breathing, digestion, etc.). This region also processes taste information and is thought to play an important role in experiencing the emotion of disgust. See Role of the insular cortex in emotion Relationship to cognitive neuroscience In its broadest sense, cognition refers to all mental processes. However, the study of cognition has historically excluded emotion and focused on non-emotional processes (e.g. memory, attention, perception, action, problem solving and mental imagery). As a result, the study of the neural basis of non-emotional and emotional processes emerged as two separate fields: cognitive neuroscience and affective neuroscience. The distinction between non-emotional and emotional processes is now thought to be largely artificial, as the two types of processes often involve overlapping neural and mental mechanisms. Thus, when cognition is taken at its broadest definition, affective neuroscience could also be called the cognitive neuroscience of emotion. Neuroscience of particlar emotions *Neuroscience of anxiety *Neuroscience of disgust *Neuroscience of empathy *Neuroscience of fear *Neuroscience of happiness See also *Arousal *Fight or flight response *Papez circuit References * Broca, P. (1878) "Anatomie comparée des circonvolutions cérébrales: le grande lobe limbique." Rev. Anthropol. 1':385-498. * Dalgleish T. (2004) "The emotional brain." ''Nature Reviews Neuroscience '''5:583-9. PMID 15208700 * Damasio AR. (1977) "The somatic marker hypothesis and the possible functions of the prefrontal cortex." Philos Trans R Soc Lond B Biol Sci. 351(1346):1413-20. PMID 894195 * Davidson, RJ & Sutton, SK (1995) "Affective neuroscience: The emergence of a discipline." Current Opinion in Neurobiology 5':217-224. PMID 7620310 * Davidson, RJ, Irwin, W. (1999) “The functional neuroanatomy of emotion and affective style.” ''Trends in Cognitive Science '''3:11-21. PMID 10234222 * Davidson, RJ (2000) "Cognitive neuroscience needs affective neuroscience (and vice versa)." Brain & Cognition 42:89-92. PMID 10739607 * Davidson, RJ (2001) "Toward a biology of personality and emotion." Annals of the NY Academy of Sciences 935:191-207. PMID 11411166 * Panksepp, J (1992) "A critical role for 'affective neuroscience' in resolving what is basic about basic emotions." Psychol Rev. 99(3):554-60. PMID 1502276 * Ledoux, JE (1995) "Emotion: clues from the brain." Annu Rev Psychol. 46:209-35. PMID 7872730 *Maclean, PD. (1952) "Some psychiatric implications of physiological studies on frontotemporal portion of limbic system (visceral brain)." Electroencephalogr Clin Neurophysiol Suppl. 4'(4):407-18. PMID 12998590 *Papez JW. (1937) "A proposed mechanism of emotion. 1937." ''J Neuropsychiatry Clin Neurosci. '''7(1):103-12. PMID 7711480 Further reading * Panksepp J. (1998) "Affective Neuroscience: The Foundations of Human and Animal Emotions (Series in Affective Science)." Oxford University Press, New York, New York. http://www.amazon.com/exec/obidos/tg/detail/-/0195096738 * Lane RD, Nadel L. (2000) "Cognitive Neuroscience of Emotion (Series in Affective Science)." Oxford University Press, New York, New York. http://www.amazon.com/exec/obidos/tg/detail/-/0195155920 See also * Affective spectrum * Bipolar disorder * Cognitive neuroscience * Emotion * Evolutionary neuroscience * Mood * Neuropsychiatry * Personality * Psychophysiology * Quantum mind * Schizoaffective disorder Category:Affective neuroscience Category:Emotion